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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Use of the U.S. General Land Office survey notes for investigating vegetation change in southern Arizona

Stoiber, Philip Edwin, 1949- January 1973 (has links)
No description available.
32

The functional role of mosses in Arctic ecosystems

Gornall, Jemma January 2005 (has links)
In arctic tundra ecosystems mosses dominant the vegetation in terms of productivity and diversity.  Despite this, mosses are often overlooked in studies of tundra ecology.  However, evidence from this thesis suggests that mosses maybe integral to the functioning of these systems.  Mosses insulate soil keeping it cooler than air temperature, an effect more apparent under deeper moss.  The effects of the moss layer on soil characteristics alter conditions for microbial populations resulting in higher nitrogen availability in soil under shallow moss.  This thesis shows that the role of mosses in determining vascular plant success may dictate many higher plant interactions.  There are both positive and negative effects of the moss layer on vascular plant growth.  The relationship between positive and negative impacts of the moss layer on vascular plants is species specific, meaning that moss cover may be a key determinate of vascular plant community structure.  Climatic warming and herbivory are important drivers of vegetation change in the Arctic.  This thesis shows that grazing by reindeer and grubbing by geese is detrimental to moss cover.  As mosses insulate the soil, a reduction in depth or integrity increases soil temperatures and enhances microbial activity and thus nitrogen availability.  This in conjunction with addition of nutrients from faeces enhances vascular plant productivity to the further detriment of mosses.  Warming increases soil temperature and accelerates decomposition, but has little affect on either biomass of moss or vascular plants.  Moss grubbing has a greater negative effect on mosses in a warmed environment.  This thesis concludes that mosses are integral to the current functioning of tundra heaths.
33

Vegetation Dynamics Over the Northeast Region of Brazil and Their Connections With Climate Variability During the Last Two Decades of the Twentieth Century.

Barbosa, Humberto January 2004 (has links) (PDF)
Thesis (Ph. D. - Soil, Water and Environmental Science)--University of Arizona, 2004. / Includes bibliographical references (leaves 175-187).
34

Characterization of fire effects on forest ecosystems in the Tillamook Forest, Oregon /

Chen, Shu-Huei. January 1997 (has links)
Thesis (M.S.)--Oregon State University, 1998. / Typescript (photocopy). Includes bibliographical references (leaves 93-100). Also available online.
35

Evaluating constraints and opportunities in managing weed populations with cover crops

Mirsky, Steven B. January 2008 (has links) (PDF)
These (Ph.D.)--Pennsylvania State University, 2008. / Title from PDF title page. Available through UMI ProQuest Digital Dissertations. Includes bibliographical references (leaves 164-171). Also issued in print.
36

Distribution patterns and metapopulation dynamics of epiphytic mosses and lichens /

Snäll, Tord. January 2003 (has links)
Thesis (doctoral)--Uppsala Universitet, 2003. / Includes bibliographical references (p. 28-33). Downloaded and printed Aug. 26, 2004; also available via the Internet.
37

Exploring the influence of land-use and climate on regional hydrology and groundwater recharge

Jayawickreme, Dushmantha Helapriya. January 2008 (has links)
Thesis (Ph. D.)--Michigan State University. Dept. of Geological Sciences, 2008. / David Hyndman, dissertation advisor--From acknowledgments. Title from PDF t.p. (viewed on Aug. 20, 2009) Includes bibliographical references (p. 148-150). Also issued in print.
38

Fire effects on vegetation diversity, structure, and successional dynamics in shrub-steppe and mixed conifer environments of the Hells Canyon, Idaho /

Havlina, Douglas William. January 1995 (has links)
Thesis (M.S.)--Oregon State University, 1995. / Typescript (photocopy). Includes bibliographical references. Also available online.
39

Alkaline wetland vegetation dynamics at North Dakota piping plover nesting beaches /

Root, Brian G. January 1996 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.
40

Alkaline wetland vegetation dynamics at North Dakota piping plover nesting beaches

Root, Brian G. January 1996 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

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